Electric heater



Feb. 16 1926. 1,573,787

c. P. RANDOLPH ELCTRIC HEATER Filed May 25, 1925 m vm., f

Inve r orLe P. rwcLoLph HLS Attorney i Patented Feb. 16, 1926.

A. UNITED STATES y 1,573,787 PATENT OFFICE.

CHARLES P. RANDOLPH, OF OAK PARK, ILLINOIS, ASSIGNOR TO EDISON ELECTRIC.APPLIANCE COMPANY, INCORPORATED, 0F CHICAGO, ILLINOIS, A. CORPORATIONOF NEW YORK.

ELECTRIC HEATER.

Application led lay 25, 1925. Serial Hol 32,529.

To all whom it may concern.'

Be it known that I, CHARLES I. RAN- 'noLr1I,`a citizen of the UnitedStates, residing at Oak Park, in the county of Cook, State of Illinois,have invented certain new and useful Improvements in Electric Heaters,of which the following is a specification.

My invention relates to electric heaters, more particularly to electricHatirons. and has for its object the provision of'a Asimple and reliabledevice of this character which may be manufactured at low cost.

. Incarrying out my invention I Secure an insulating heating 'resistanceconductor in a groove inthe top of the body to be heated.

For a more complete understanding of my invention reference should be.had to the accompanying'drawing in which Fig. 1 is a sectional view,l ofan 'electric atiron em.- bodying my invention while Fig. 2 is a planview with the cover and various other arts removed showing thearrangement o the heating unit.

Referring to the'drawing, in the form of my invention disclosed I haveshow n a mass of heat conducting material 10, such as cast iron, forminga atiron bodyof conventional outline and being provided on its lowerside with'an .ironing face 11. The flatiron body 1() is provided atthe'top with a central upwardly projecting portion 12 havingsubstantially the same outline as the lower portion whereby a ledge 13is formed around the atiron body on which rests a suitable cover 14. Thecover is secured to the {iatiron body by means of screws 15 and 16./

These screws also ass .through and secure a suitable handle 1 The cover14 iscentrally located on the atiron body by means ofY stops orprojections 18 to 22 inclusive spaced along-the sides of the raisedportlon 12.`

In the upper surface of the raised portion 12 a groove 23 is provided,having substanuconstructed substantially in accordance with torv 26embedded in powdered electrically insulating material 27. The sheath 25is preferably formed of seamless tubing. The powdered insulatingmaterial is compacted to a hard dense mass by reducing the diameter ofthe sheath, for example, by rolling or swaging, and forms an excellentinsu ator and also an eliicient conductor yo heat fromcthe resistanceconductor to the sheath. In the arrangement shown the sheath is shapedwith a substantially Square cross section and is of such size asitolitquite closely in the groove 23.

A clamping plate is provided having its edge bent downward so as toforma ridge 29, which rests on the heating unit 24. This clamping plate isSecured to the body 10 by means of screws 30, and the heating Vunit isthereby clamped firmly in the groove. It will be observed that the lowerfiat side of the heating unit is pressed firmly against the flat bottomof the groove and is thus maintained in good thermal relation therewith.The sides of the groove are inclose proximity to the heating unit andreceive a certain amount of heat by radiation and conduction. Theflatiron body 10 is preferably cast, the groove 23 being formed in it upon casting. The only machine Work necessary, therefore, is thatrequired -to finish the ironing face 11. f

The resistance conductor 26 has its ends connected to terminal members31 and 32 which in turn are connected to contact pins 33 carried by thecover 14. A. suitable guard34: surrounds the contact pins. An electricalconnection is established between a suitable supply circuit andthecontact pins by means of an attachment plug of any well known form.

It will be observed that my invention lends itself to a simple andrugged low cost construction throughout the device. The heating unit,which is the most prolific source of trouble in electric. appliances,is`

of particularly rugged construction: The .arrangement of the heatingunit w1th re spect to the heated body the eiiicicnt conduction of heatfromY the resistance con- 1,367,341 -to Abbott 'dated ductor to theheated b0dy, facilitates the production of the heated body at low cost,and promotes ease and quickness of .assembly. Furthermore, the heatingunit can be removed very easily at any time for repairs or renewal.

While I have described my invention as embodied in concrete form and asoperating in a specific manner in accordance with the provisions of thepatent statutes, it should be understood that I do not limit my in-.vention thereto, since various modifications thereof will suggestthemselves to those skilled in the art without departing from the spiritof my invention, the` scope of which is set forth in the annexed claims.

lVhat I claim as new and desire 'to secure by Letters Patent of theUnited States, is

l. The combination with a mass of heat conducting material provided witha substantially flat-bottom groove, of a heating unit encased in acontinuous unbroken metallic shea-th clamped in said groove, said sheathbeing formed with a substantially flat surface held in engagement withthe bottom of said groove in good thermal relation therewith. y

2. The combination with a mass of heat conducting material provided witha flatbottom groove having a depth substantially equalto its width, aresistance conductor encased in a continuous unbroken metallic sheathshaped to have a substantially square cross section fitting closely insaid groove, and means for clamping said sheath in said groove so thatone side thereof is held in intimate thermal relation with the bottom ofsaid groove.

3. The combination with amass of heat conducting material provided witha flatbottom groove having a depth substantially equal to its width, ahelical resistance conductor, a sheath of seamless metal tubingsurrounding said resistance conductor, powdered heat refractoryinsulating material in said sheath compacted to a hard dense mass aroundsaid resistance conductor by reducing the diameter of said sheath, saidsheath being shaped during the reducing operation to have asubstantially square cross section fitting closely in said groove, andmeans for clamping said sheath 1n said groove so that oney side thereofis held in intimate thermal relation with the bottom of said groove.

In Witness whereof, I have hereunto setV my hand this 21st day of May,1925.

CHARLES P. RANDOLPH.

